Repurposing item drops.

Mushrooms=Used to create poisonous arrows. Can be used to brew potions.
Bones=Can be used as temporary weapons. Breaks fairly easily, but can be thrown.
Gunpowder=Used to create ammo for cannons, can be used in enchantments.
Rotten flesh=Eating rotten flesh gives you hunger poison (like in vanilla) and causes monsters to aggro you
temporarily. Can also be used as short-term bait for monsters
String=Used to create rope/grappling hook arrows. Can be used to create trip arrows (explosive arrows that
can be used as traps)
Spider eyes=Eating a spider eye will give you hunger poison (as usual), but also reveals monsters behind walls
and past your line of sight in a limited area. Can be used in an enhancement involving an Oracle's Elixir-
style buff.